The present invention relates generally to an outboard motor, and in particular to positioning of a control cable for controlling an amount by which a throttle valve of a throttle valve device of the outboard motor is opened.
Known outboard motors for boats include engines having vertically extending crankshafts, and auxiliary devices attached to the engines. The engines and auxiliary devices thereof are covered with engine covers. Under covers are provided below the engine covers. Provided below the under covers are extension cases. Gearboxes are mounted under the extension cases. Vertical shafts extend downwardly from the crankshafts. The vertical shafts are connected to gears disposed within the gearboxes. Motive power supplied from the engines is transmitted through the vertical shafts and the gears to propellers provided behind the gearboxes to thereby thrust the boats. The outboard motors are mounted to sterns of the boats via stern brackets in such a manner as to pivot in an up-and-down direction.
Amounts by which throttle valves of carburetors are opened are controlled by control cables to be operated by throttle grips positioned on hulls of the boats. Recently, large-sized engines for outboard motors have become popular. For such a large-sized engine, throttle valves are often positioned in a rear part of an engine compartment of an outboard motor, as disclosed in Japanese Utility Model Registration Publication No. 2577611.
The control cable extends through an engine cover out of the outboard motor. Within the engine cover, there are closely accommodated auxiliary devices of an engine as well as the carburetors to thereby provide a limited space for disposition of the control cable. The control cable should thus inevitably extend through the auxiliary devices, or otherwise be disposed in a tortuous line to avoid undesirable contact with the auxiliary devices.
The cable thus arranged is difficult to operate.
An object of the present invention is to provide an outboard motor including a throttle valve device connected to a control cable disposed in a less complicated configuration within a small space formed in an engine compartment, such that the throttle valve is smoothly operated.
According to an aspect of the present invention, there is provided an outboard motor comprising: an engine; an induction silencer disposed above the engine; a throttle valve device disposed adjacent the induction silencer; an intake manifold disposed adjacent the throttle valve device; an engine cover for covering the engine, the induction silencer, the throttle valve device, and the intake manifold; and a control cable for opening and closing a throttle valve of the throttle valve device; the induction silencer including a connecting port communicating with an upstream portion of the throttle valve device; the throttle valve device having a downstream portion communicating with an upstream portion of the intake manifold; the control cable including a first cable portion extending over an upper surface of the induction silencer.
The control cable is disposed on the surface of the induction silencer positioned adjacent the throttle valve device. This means that a large space formed above the induction silencer is effectively used for disposition of the control cable.
This arrangement eliminates the need for the control cable to be disposed alongside a cylinder block or a cylinder head of the engine. Further, there is no need to provide the cylinder block and the like with any particular member for clamping the control cable against the cylinder block.
The control cable does not extend around the engine, and hence the engine cover has a reduced width to thereby provide a decreased size of the outboard motor. The thus arranged outboard motor provides an improved outer appearance.
In a preferred form of the present invention, the first cable portion extends in the front-and-rear direction of the induction silencer.
This arrangement has the advantage that the control cable does not interfere with the engine and auxiliary devices attached to the engine.
Because the control cable extends in the front-and-rear direction of the induction silencer, the control cable can be readily replaced with new one with the engine cover removed.
In a further preferred form of the present invention, the control cable further includes a second cable portion extending in the right-and-left direction of the induction silencer.
In a still further preferred form of the present invention, the first cable portion is received in an engagement groove formed on the upper surface of the induction silencer.
Formation of the engagement groove makes it possible to hold the control cable to the surface of the upper member.